It is known in the art of growing plants hydroponically to use a rotatable drum with an interior lamp, thereby providing for efficient the use of light. Marchildon, U.S. Pat. No. 6,604,321, discloses a rotary plant-growing apparatus with an open-ended cylindrical drum which rotates about a horizontal axis on a support stand. A lamp is positioned at the axis of the drum. The drum holds plant containers, with the plants facing the light and the bottom of the containers extending radially outward from the drum. A trough of water under the drum is spaced from the drum such that the lower part of the containers contacts the water as the drum rotates, watering the plants.
Marchildon, WO 2004/045273, discloses a plant-growing apparatus having a plurality of rotatable plant-growing modules which can be moved around a circuit in the apparatus. Each module comprises a cylindrical structure for holding plant-growing containers in which the plants grow radially inwardly towards a lamp. The modules are supported and rotated in a horizontal position as they are moved.
The present invention is directed to developments in systems for growing plants using rotatable cylindrical structures.